Infectious diseases are leading causes of morbidity and mortality worldwide. Increasingly, infectious agents are developing resistance to antimicrobials and antivirals; new strategies are needed to better control the spread of infection. The keys to these strategies lie in the interfaces among epidemiology, mathematics, statistics, microbiology and medicine. By applying population approaches to the study of infectious agents, new treatment and prevention strategies can be identified and evaluated. These complex problems require individuals trained to integrate information and skills across multiple disciplines. There is a severe shortage of individuals with this training. The goal of the Interdisciplinary training Program in Infectious Diseases (IPID) is to teach students to conduct multi-pronged studies in order to address problems arising from infectious agents that affect human health. This is a dual mentorship program: initially each student will be assigned two advisors each with expertise in a different core discipline. Students will be trained to conceptualize research problems using mathematical tools, to design appropriate population-based studies to address the problem using either laboratory or field methods, and to analyze and apply the study results. All students will gain practical expertise in the laboratory, in data collection, in data analysis, and in modeling. Following a year coursework, and opportunities to interact with faculty formally and informally, students will choose two mentors representing different core expertise to serve as mentors. This program is novel in that it formally integrates modeling techniques, and theoretical and practical experience in the laboratory and field. The ability to do so is extremely powerful. We are unaware of other programs in infectious disease which formally train students across these disciplines. IPlD is currently funded by the center for Molecular and Clinical Epidemiology of infectious Diseases (MAC-EPID) and the Center for the Study of Complex Systems (CSCS) and has four pre-doctoral students and one post-doctoral fellow. We are requesting funding for four pre-doctoral and two post-doctoral fellowships.